The present invention relates to a sensor that is used for sensing and indication of the stroke position of a hydraulic cylinder, that is, indicating the amount of extension or the position of the rod of a hydraulic cylinder from a reference. The sensor is made so it can be installed and removed without disassembly of the cylinder. The sensor installs in the base end of the cylinder tube and can be tightened in place and removed with a sensor connection wire attached to the sensor.
It is desirable to have stroke or position sensing and indicating capabilities in a hydraulic cylinder used for various applications, such as on skid steer loaders, to provide information as to the position of lift arms of a loader or the position of various parts on attachments that are moved by hydraulic actuators. In particular, position sensors can be used, for example, where the fluid pressure cylinder extends a loader lift arm. Another use is for cylinders that are part of a steering system. Installation and removal of existing sensors for service and even for initial assembly has been a problem, and generally requires multiple parts and difficult positioning and potential for damage.
For example, U.S. Pat. No. 6,509,733 shows a fluid cylinder that has an internal stroke sensor, and the sensor itself is not accessible from the exterior of the cylinder when the cylinder is assembled.
U.S. Pat. No. 6,509,733 shows a type of sensor that could be installed or mounted as disclosed herein, and other types of sensors usable for sensing stroke or position include magnetostrictive linear displacement devices, sensors that have transmitters and receivers, and LVDT sensors.
The present invention is directed to providing a construction and method of installing a sensor into a base end of a fluid cylinder after the cylinder is otherwise assembled with a piston and piston rod, and which can be removed without substantial disassembly of the cylinder.